The present invention relates generally to valves and to vacuum boosters, and more particularly to a solenoid valve, to a vacuum booster diaphragm subassembly, and to a vacuum booster assembly.
Conventional solenoid valves include those having a solenoid actuation rod having a valve end which engages a valve seat to block fluid passage and which disengages from the valve seat to allow fluid passage. One known application of a conventional solenoid valve is to allow or block passage of air to a chamber of a vacuum booster of a vehicle braking system. Conventional vacuum boosters include tandem vacuum boosters having primary and secondary vacuum and working chambers, a primary diaphragm dividing the primary working and vacuum chambers, and a secondary diaphragm dividing the secondary working and vacuum chambers.
What is needed is an improved solenoid valve useful for many applications including, but not limited to, a vacuum booster of a vehicle braking system. What also is needed is an improved secondary diaphragm for a vacuum booster. What additionally is needed is an improved vacuum booster assembly.
A first expression of a first embodiment of the invention is for a solenoid valve including a solenoid actuation rod, first and second tip valves, and a solenoid valve housing having first, second, and third valve ports. The first tip valve is actuated by the first end of the solenoid actuation rod to allow or block fluid passage through the first valve port, wherein fluid can flow between the first and third valve ports when the first tip valve is open. The second tip valve is actuated by the second end of the solenoid actuation rod to allow or block fluid passage through the second valve port, wherein fluid can flow between the second and third valve ports when the second tip valve is open.
A second expression of the first embodiment of the invention is for a vacuum booster diaphragm subassembly including a vacuum booster diaphragm and a grommet attached to the vacuum booster diaphragm. The vacuum booster diaphragm is installable in a vacuum booster assembly having primary and secondary working chambers such that the grommet allows fluid flow between the secondary working chamber and a region outside the vacuum booster assembly.
A third expression of the first embodiment of the invention is for a vacuum booster assembly including a vacuum booster and a solenoid valve. The vacuum booster has a primary working chamber with a primary outside port, a primary vacuum chamber, a primary diaphragm dividing the primary working and vacuum chambers, a secondary working chamber with a secondary outside port, a secondary vacuum chamber, a secondary diaphragm dividing the secondary working and vacuum chambers, and a grommet attached to the secondary diaphragm. The solenoid valve is identical to the solenoid valve previously described in the first expression, wherein the solenoid valve housing is attached to the vacuum booster with the first port in fluid communication with the primary port, with the second port in fluid communication with the atmosphere, and with the third port in fluid communication with the secondary port through the grommet.
Several benefits and advantages are derived from one or more of the expressions of the first embodiment of the invention. The tip valves of the solenoid valve provide large openings to allow for high fluid flow. The grommet of the vacuum booster diaphragm subassembly allows fluid flow between the secondary working chamber and a region outside the vacuum booster assembly. The vacuum booster assembly, when used in a vehicle braking system, provides the ability to quickly apply brake pressure.